I recall being told, too many years ago to remember exactly when or by whom, that what distinguishes a neurologist from other physicians is an understanding of the peripheral nervous system. While that knowledge may not be the only remarkable feature of neurologists, it is surely true that familiarity with the anatomy, physiology, and disorders of the peripheral nervous system is a requisite for the successful performance of the duties of our profession. Thus, you will find this issue of CONTINUUM, devoted to peripheral neuropathy and organized by guest editor Dr David Simpson, critically important.
The opening article by Drs Adina Alport and Howard Sander sets the stage by clearly delineating a clinical approach to peripheral neuropathy, including anatomic localization and diagnostic testing. Several of the subsequent articles feature a categorical approach to peripheral neuropathy, beginning with a discussion of genetic neuropathies by Drs Agnes Patzko and Michael Shy. While Charcot-Marie-Tooth disease has been the touchstone of this group of disorders, an explosion of genetic information has sometimes led to bewilderment for the clinician. The authors provide a clear review of this field that helps us recognize patients with genetic neuropathies as well as organize our thinking about them. Probably no other systemic disease rivals diabetes mellitus in the frequency and variety of ways in which it affects the peripheral nervous system. Drs A. Gordon Smith and J. Robinson Singleton lead us through the array of diabetic neuropathies. However, diabetes is by no means the only metabolic disturbance that affects the peripheral nerves. In a subsequent article, Drs Brett Morrison and Vinay Chaudhry guide us through other metabolic conditions; in addition, they review the many toxins that can injure the peripheral nervous system. These authors also cover the effects of vitamin deficiency states—and occasionally vitamin excess—on the peripheral nerves, discussing not only the well-known consequences of vitamin B12 deficiency but also the ramifications of many other deficiencies. Dr Yuen So brings us up-to-date on the vital subject of immune-mediated neuropathies, highlighting both Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy. These neuropathies are particularly important because they are responsive to treatment. In the last article devoted to a specific disease category, Dr Jessica Robinson-Papp focuses on infectious neuropathies. While she devotes considerable attention to the still-enigmatic peripheral nervous system manifestations of HIV infection, Dr Robinson-Papp goes well beyond that to review the panoply of infectious neuropathies caused by other viruses, bacteria, and parasites.
A hallmark of many peripheral neuropathies is pain, which often carries rather distinctive qualities. Dr Justin McArthur reviews the subject of painful small fiber neuropathies, emphasizing the clinical features, pathologic mechanisms, diagnostic testing, and treatment. Dr Nadine Attal extends the discussion of neuropathic pain with further emphasis on management, including an important analysis of the interpretation of clinical trials. Exploration of issues related to pain management continues in the Ethical Perspectives section as Dr Kathryn Elliott explores the thorny question of opioid administration in a former heroin user with depression. Then, in the Practice section, Drs John England and Gary Franklin amplify the discussion of the treatment of chronic neuropathic pain with opioids.
Dr Peter Donofrio tackles the matter of coding related to peripheral neuropathy in this issue. Finally, CONTINUUM is pleased to introduce a new feature, Guidelines in Practice, which illustrates the application of AAN guidelines in practice. Dr Anant Shenoy kicks off this addition to CONTINUUM with a case discussion focused on the treatment of painful diabetic neuropathy.
As always, you can enrich your CONTINUUM experience by working through the multiple-choice questions, crafted for this issue by Drs Douglas Gelb and D. Joanne Lynn. The Patient Management Problem, devised by Drs Anila Thomas and Robinson-Papp, completes the package.
Dr Simpson and colleagues have provided an enormous service with their thorough coverage of a critically important topic. We will all be more complete neurologists for their efforts.
—Aaron E. Miller, MD